How to import an object into an Armory game scene while the game is running?
If you mean add an object into the scene, you use the import. Click file in the top right, hover over import, and click wavefront for an OBJ, Then import what you want to. If you mean have it go into the game at a certain point, that'd take other scripts. I don't really know what you mean by a game, I assume you're making a game.